#line 2 "/root/AtCoder/Halc-Library/Template/Template.hpp"
#include <bits/stdc++.h>
using namespace std;

#line 8 "/root/AtCoder/Halc-Library/Template/InOut.hpp"
inline void scan() {}
inline void scan(int32_t &a) { std::cin >> a; }
inline void scan(uint32_t &a) { std::cin >> a; }
inline void scan(int64_t &a) { std::cin >> a; }
inline void scan(uint64_t &a) { std::cin >> a; }
inline void scan(char &a) { std::cin >> a; }
inline void scan(float &a) { std::cin >> a; }
inline void scan(double &a) { std::cin >> a; }
inline void scan(long double &a) { std::cin >> a; }
inline void scan(std::vector<bool> &vec) {
    for (int32_t i = 0; i < vec.size(); i++) {
        int a;
        scan(a);
        vec[i] = a;
    }
}
inline void scan(std::string &a) { std::cin >> a; }
template <class T>
inline void scan(std::vector<T> &vec);
template <class T, size_t size>
inline void scan(std::array<T, size> &vec);
template <class T, class L>
inline void scan(std::pair<T, L> &p);
template <class T, size_t size>
inline void scan(T (&vec)[size]);
template <class T>
inline void scan(std::vector<T> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T>
inline void scan(std::deque<T> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T, size_t size>
inline void scan(std::array<T, size> &vec) {
    for (auto &i : vec) scan(i);
}
template <class T, class L>
inline void scan(std::pair<T, L> &p) {
    scan(p.first);
    scan(p.second);
}
template <class T, size_t size>
inline void scan(T (&vec)[size]) {
    for (auto &i : vec) scan(i);
}
template <class T>
inline void scan(T &a) {
    std::cin >> a;
}
inline void in() {}
template <class Head, class... Tail>
inline void in(Head &head, Tail &...tail) {
    scan(head);
    in(tail...);
}
inline void print() { std::cout << ' '; }
inline void print(const bool &a) { std::cout << a; }
inline void print(const int32_t &a) { std::cout << a; }
inline void print(const uint32_t &a) { std::cout << a; }
inline void print(const int64_t &a) { std::cout << a; }
inline void print(const uint64_t &a) { std::cout << a; }
inline void print(const char &a) { std::cout << a; }
inline void print(const char a[]) { std::cout << a; }
inline void print(const float &a) { std::cout << a; }
inline void print(const double &a) { std::cout << a; }
inline void print(const long double &a) { std::cout << a; }
inline void print(const std::string &a) {
    for (auto &&i : a) print(i);
}
template <class T>
inline void print(const std::vector<T> &vec);
template <class T, size_t size>
inline void print(const std::array<T, size> &vec);
template <class T, class L>
inline void print(const std::pair<T, L> &p);
template <class T, size_t size>
inline void print(const T (&vec)[size]);
template <class T>
inline void print(const std::vector<T> &vec) {
    if (vec.empty()) return;
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T>
inline void print(const std::deque<T> &vec) {
    if (vec.empty()) return;
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T, size_t size>
inline void print(const std::array<T, size> &vec) {
    print(vec[0]);
    for (auto i = vec.begin(); ++i != vec.end();) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T, class L>
inline void print(const std::pair<T, L> &p) {
    print(p.first);
    std::cout << ' ';
    print(p.second);
}
template <class T, size_t size>
inline void print(const T (&vec)[size]) {
    print(vec[0]);
    for (auto i = vec; ++i != end(vec);) {
        std::cout << ' ';
        print(*i);
    }
}
template <class T>
inline void print(const T &a) {
    std::cout << a;
}
inline void out() { std::cout << '\n'; }
template <class T>
inline void out(const T &t) {
    print(t);
    std::cout << '\n';
}
template <class Head, class... Tail>
inline void out(const Head &head, const Tail &...tail) {
    print(head);
    std::cout << ' ';
    out(tail...);
}
inline void Yes(bool i = true) { out(i ? "Yes" : "No"); }
inline void No(bool i = true) { out(i ? "No" : "Yes"); }
inline void Takahashi(bool i = true) { out(i ? "Takahashi" : "Aoki"); }
inline void Aoki(bool i = true) { out(i ? "Aoki" : "Takahashi"); }
inline void Alice(bool i = true) { out(i ? "Alice" : "Bob"); }
inline void Bob(bool i = true) { out(i ? "Bob" : "Alice"); }
inline void First(bool i = true) { out(i ? "First" : "Second"); }
inline void Second(bool i = true) { out(i ? "Second" : "First"); }
inline void Possible(bool i = true) { out(i ? "Possible" : "Impossible"); }
inline void Impossible(bool i = true) { out(i ? "Impossible" : "Possible"); }
inline void fls() { std::flush(std::cout); }
struct IOsetup {
    IOsetup() {
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
        std::cout << std::fixed << std::setprecision(16);
    }
} iosetup;
#line 9 "/root/AtCoder/Halc-Library/Template/Util.hpp"
using ll = int64_t;
using ld = long double;
using ull = uint64_t;
using uint = uint32_t;
using pll = std::pair<ll, ll>;
using pii = std::pair<int32_t, int32_t>;
using vl = std::vector<ll>;
using vvl = std::vector<std::vector<ll>>;
using pdd = std::pair<ld, ld>;
using tuplis = std::array<ll, 3>;
template <class T>
using pq = std::priority_queue<T, std::vector<T>, std::greater<T>>;
constexpr ll LINF = (1LL << 62) - (1LL << 31);
constexpr int32_t INF = INT_MAX >> 1;
constexpr ll MINF = 1LL << 40;
constexpr ld DINF = std::numeric_limits<ld>::infinity();
constexpr int32_t MODD = 1000000007;
constexpr int32_t MOD = 998244353;
constexpr ld EPS = 1e-9;
constexpr ld PI = 3.1415926535897932;
const ll four[] = {0, 1, 0, -1, 0};
const ll eight[] = {0, 1, 1, 0, -1, -1, 1, -1, 0};
template <class T>
bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return true;
    } else
        return false;
}
template <class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    } else
        return false;
}
template <class T>
ll sum(const T &a) {
    return accumulate(std::begin(a), std::end(a), 0LL);
}
template <class T>
ld dsum(const T &a) {
    return accumulate(std::begin(a), std::end(a), 0.0L);
}
template <class T>
auto min(const T &a) {
    return *min_element(std::begin(a), std::end(a));
}
template <class T>
auto max(const T &a) {
    return *max_element(std::begin(a), std::end(a));
}
#line 1 "/root/AtCoder/Halc-Library/Template/Macro.hpp"
#define _overload3(_1, _2, _3, name, ...) name
#define _overload4(_1, _2, _3, _4, name, ...) name
#define _rep1(i, n) for (int64_t i = 0; i < (n); i++)
#define _rep2(i, a, b) for (int64_t i = (a); i < (b); i++)
#define _rep3(i, a, b, c) for (int64_t i = (a); i < (b); i += (c))
#define rep(...) _overload4(__VA_ARGS__, _rep3, _rep2, _rep1)(__VA_ARGS__)
#define _rrep1(i, n) for (int64_t i = (n) - 1; i >= 0; i--)
#define _rrep2(i, a, b) for (int64_t i = (b) - 1; i >= (a); i--)
#define rrep(...) _overload3(__VA_ARGS__, _rrep2, _rrep1)(__VA_ARGS__)
#define each(i, ...) for (auto&& i : __VA_ARGS__)
#define all(i) std::begin(i), std::end(i)
#define rall(i) std::rbegin(i), std::rend(i)
#define len(x) ((int64_t)(x).size())
#define fi first
#define se second
#define uniq(x) x.erase(unique(all(x)), std::end(x))
#define vec(type, name, ...) vector<type> name(__VA_ARGS__);
#define vv(type, name, h, ...) std::vector<std::vector<type>> name(h, std::vector<type>(__VA_ARGS__));
#define INT(...) int32_t __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) int64_t __VA_ARGS__; in(__VA_ARGS__)
#define ULL(...) uint64_t __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) std::string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) long double __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) std::vector<type> name(size); in(name)
#define VV(type, name, h, w) std::vector<std::vector<type>> name(h, std::vector<type>(w)); in(name)
#line 3 "/root/AtCoder/Halc-Library/Modint/Modint.hpp"

#line 6 "/root/AtCoder/Halc-Library/Modint/Modint.hpp"
template <uint64_t Mod>
struct Modint {
    uint64_t x;
    constexpr Modint() noexcept { x = 0; }
    constexpr Modint(int64_t val) noexcept {
        x = (val < 0 ? val % (int64_t)(Mod) + Mod : val % Mod);
    }
    inline uint64_t _get_mod(uint64_t val) noexcept {
        const static uint64_t m_inv = (-1ULL) / Mod + 1;
        uint64_t ret = ((unsigned __int128)(val)*m_inv) >> 64;
        uint64_t pro = ret * Mod;
        return (val - pro + (val < pro ? Mod : 0));
    }
    friend std::ostream &operator<<(std::ostream &os, Modint &b) noexcept {
        return os << b.x;
    }
    friend std::istream &operator>>(std::istream &is, Modint &b) noexcept {
        return is >> b.x;
    }
    constexpr uint64_t val() noexcept { return x; }
    constexpr Modint operator+() noexcept { return (*this); }
    constexpr Modint operator-() noexcept { return Modint() - (*this); }
    friend Modint operator+(const Modint lhs, const Modint rhs) noexcept {
        return Modint(lhs) += rhs;
    }
    friend Modint operator-(const Modint lhs, const Modint rhs) noexcept {
        return Modint(lhs) -= rhs;
    }
    friend Modint operator*(const Modint lhs, const Modint rhs) noexcept {
        return Modint(lhs) *= rhs;
    }
    friend Modint operator/(const Modint lhs, const Modint rhs) {
        return Modint(lhs) /= rhs;
    }
    constexpr Modint &operator+=(const Modint rhs) noexcept {
        x += rhs.x;
        if (x >= Mod) x -= Mod;
        return *this;
    }
    constexpr Modint &operator-=(const Modint rhs) noexcept {
        if (x < rhs.x) x += Mod;
        x -= rhs.x;
        return *this;
    }
    constexpr Modint &operator*=(const Modint rhs) noexcept {
        x = _get_mod(x * rhs.x);
        return *this;
    }
    friend bool operator==(const Modint lhs, const Modint rhs) noexcept {
        return lhs.x == rhs.x;
    }
    friend bool operator!=(const Modint lhs, const Modint rhs) noexcept {
        return rhs.x != rhs.x;
    }
    constexpr Modint &operator/=(Modint rhs) { return (*this) *= rhs.inv(); }
    constexpr Modint inv() {
        int64_t a = (*this).x, b = get_mod();
        assert(a != 0);
        int64_t s = b, t = a;
        int64_t m0 = 0, m1 = 1;
        while (t) {
            int64_t u = s / t;
            s -= t * u;
            m0 -= m1 * u;
            int64_t tmp = s;
            s = t;
            t = tmp;
            tmp = m0;
            m0 = m1;
            m1 = tmp;
        }
        assert(s == 1);
        if (m0 < 0) m0 += b;
        return Modint(m0);
    }
    constexpr Modint pow(uint64_t x) noexcept {
        Modint ret = 1;
        Modint bin = (*this);
        while (x) {
            if (x & 1) ret *= bin;
            bin *= bin;
            x >>= 1;
        }
        return ret;
    }
    static uint64_t get_mod() noexcept { return Mod; }
};

template <int64_t id>
struct ArbitraryModint {
    uint64_t x;
    static uint64_t &mod() noexcept {
        static uint64_t Mod = 0;
        return Mod;
    }
    constexpr ArbitraryModint() noexcept { x = 0; }
    constexpr ArbitraryModint(int64_t val) noexcept {
        x = (val < 0 ? val % (int64_t)(get_mod()) + get_mod()
                     : val % get_mod());
    }
    inline uint64_t _get_mod(uint64_t val) noexcept {
        const static uint64_t m_inv = (-1ULL) / get_mod() + 1;
        uint64_t ret = ((unsigned __int128)(val)*m_inv) >> 64;
        uint64_t pro = ret * get_mod();
        return (val - pro + (val < pro ? get_mod() : 0));
    }
    friend std::ostream &operator<<(std::ostream &os,
                                    ArbitraryModint &b) noexcept {
        return os << b.x;
    }
    friend std::istream &operator>>(std::istream &is,
                                    ArbitraryModint &b) noexcept {
        return is >> b.x;
    }
    constexpr uint64_t val() noexcept { return x; }
    constexpr ArbitraryModint operator+() noexcept { return (*this); }
    constexpr ArbitraryModint operator-() noexcept {
        return ArbitraryModint() - (*this);
    }
    friend ArbitraryModint operator+(const ArbitraryModint lhs,
                                     const ArbitraryModint rhs) noexcept {
        return ArbitraryModint(lhs) += rhs;
    }
    friend ArbitraryModint operator-(const ArbitraryModint lhs,
                                     const ArbitraryModint rhs) noexcept {
        return ArbitraryModint(lhs) -= rhs;
    }
    friend ArbitraryModint operator*(const ArbitraryModint lhs,
                                     const ArbitraryModint rhs) noexcept {
        return ArbitraryModint(lhs) *= rhs;
    }
    friend ArbitraryModint operator/(const ArbitraryModint lhs,
                                     const ArbitraryModint rhs) {
        return ArbitraryModint(lhs) /= rhs;
    }
    constexpr ArbitraryModint &operator+=(const ArbitraryModint rhs) noexcept {
        x += rhs.x;
        if (x >= mod()) x -= mod();
        return *this;
    }
    constexpr ArbitraryModint &operator-=(const ArbitraryModint rhs) noexcept {
        if (x < rhs.x) x += mod();
        x -= rhs.x;
        return *this;
    }
    constexpr ArbitraryModint &operator*=(const ArbitraryModint rhs) noexcept {
        x = _get_mod(x * rhs.x);
        return *this;
    }
    friend bool operator==(const ArbitraryModint lhs,
                           const ArbitraryModint rhs) noexcept {
        return lhs.x == rhs.x;
    }
    friend bool operator!=(const ArbitraryModint lhs,
                           const ArbitraryModint rhs) noexcept {
        return rhs.x != rhs.x;
    }
    constexpr ArbitraryModint &operator/=(ArbitraryModint rhs) {
        return (*this) *= rhs.inv();
    }
    constexpr ArbitraryModint inv() {
        int64_t a = (*this).x, b = get_mod();
        assert(a != 0);
        int64_t s = b, t = a;
        int64_t m0 = 0, m1 = 1;
        while (t) {
            int64_t u = s / t;
            s -= t * u;
            m0 -= m1 * u;
            int64_t tmp = s;
            s = t;
            t = tmp;
            tmp = m0;
            m0 = m1;
            m1 = tmp;
        }
        assert(s == 1);
        if (m0 < 0) m0 += b;
        return ArbitraryModint(m0);
    }
    constexpr ArbitraryModint pow(uint64_t x) noexcept {
        ArbitraryModint ret = 1;
        ArbitraryModint bin = (*this);
        while (x) {
            if (x & 1) ret *= bin;
            bin *= bin;
            x >>= 1;
        }
        return ret;
    }
    static void set_mod(const uint64_t x) noexcept { mod() = x; }
    static uint64_t get_mod() noexcept { return mod(); }
};
template <uint64_t N>
inline void scan(Modint<N> &a) {
    std::cin >> a.x;
}
template <int64_t id>
inline void scan(ArbitraryModint<id> &a) {
    std::cin >> a.x;
}
template <uint64_t N>
inline void print(Modint<N> a) {
    std::cout << a.x;
}
template <int64_t id>
inline void print(ArbitraryModint<id> a) {
    std::cout << a.x;
}
#line 4 "/root/AtCoder/Halc-Library/Math/ModCombination.hpp"
template <typename T>
struct ModCombination {
    std::vector<T> fact = {1}, rev{1};
    ModCombination(uint32_t sz = 0) {
        fact.reserve(sz+1);
        rev.reserve(sz+1);
    }
    void resize(uint32_t sz) {
        sz++;
        if (fact.size() >= sz) return;
        uint32_t before = fact.size();
        fact.resize(sz);
        rev.resize(sz);
        for (uint32_t i = before; i < sz; i++) {
            fact[i] = fact[i - 1] * i;
            rev[i] = rev[i - 1] / i;
        }
    }
    T comb(int32_t n, int32_t k) {
        if (n < 0 || k < 0 || n < k) return 0;
        resize(n);
        return fact[n] * rev[n - k] * rev[k];
    }
    T perm(int32_t n, int32_t k) {
        if (n < 0 || k < 0 || n < k) return 0;
        resize(n);
        return fact[n] * rev[n - k];
    }
    T multi_comb(int32_t n, int32_t k) {
        if (k == 0) return 1;
        return comb(n + k - 1, k);
    }
};
#line 4 "main.cpp"
using mint=Modint<MOD>;
ModCombination<mint> cb;
void solve() {
    LL(N,K);
    VEC(ll,A,N);
    sort(all(A));
    mint bef=N;
    mint ans=0;
    rep(i,N){
        mint now=0;
        mint inv=cb.comb(N,i+1).inv();
        rep(j,N){
            ll cnt=max(0L,j-K);
            if(j==0)cnt+=N;
            else cnt+=max(0L,N-j-K);
            now+=cb.comb(cnt,i+1)*inv;
            /*
            ll cnt=max(0L,j-K)+(N-1-j);
            now+=1-(cb.comb(N-1,i)-cb.comb(cnt,i))*inv;*/
        }
        ans+=(bef-now)*A[i];
        bef=now;
    }
    out(ans*cb.fact[N]);
}
int main() { solve(); }
/*---------------------✂ｷﾘﾄﾘ線✂----------------------*\
| Coding by hirayuu_At.                                 |
|                                                       |
|     (　ﾟдﾟ)                                           |
| ＿(__つ/￣￣￣/＿             ∧∧                    |
|     ＼/  WA  /               /⌒ヽ)                   |
|        ￣￣￣     ／＼      i三  ∪                   |
|          . ∵ .／  .／|    〇三  |                    |
|             ∴ ＼／ ／       (/~∪                    |
|      (ﾉﾟДﾟ)ﾉ    |／           三三           終       |
|     /    /                   三三        制作・著作   |
| ￣￣￣￣￣￣                三三三       ━━━━━━━━━━   |
|                                           ⒽⒶⓁⒸ    |
\*-----------------------✂ｷﾘﾄﾘ線✂--------------------*/